Rubella is most common in school-age children and adolescents, and more than 80% of the population is positive for the virus. Pregnant women infected with rubella virus before 20 weeks of gestation have a higher incidence of fetal teratogenicity. Rubella virus infection in adults and children causes a skin rash. Clinical significance Abnormal results: rubella-IgM positive: usually appears within 2 weeks of infection, peaks after the appearance of rubella and lasts for one or two months; rubella-IgG positive: usually appears two or three weeks after infection. It peaks within six months and can persist for several years. People to be tested: Patients with rubella skin rash, pregnant women Precautions Preparation for the test: You should have an empty stomach on the morning of the blood test. The IgM antibody should be tested within the first 5-15 days of the onset of the disease for the highest positive rate, while the IgG antibody rises 2 weeks after the onset of the disease. Unsuitable groups: There are no unsuitable groups. ELISA is an enzyme-linked immunoassay (ELISA), which centers on the binding of antibodies to an enzyme complex and then detects them by color development. Steps: ELISA uses serum to detect, first the blood has to undergo at least half an hour of agglutination, then the serum is taken to dilute the enzyme complex with diluent, plus serum and negative and positive controls, and also the quality control. After an hour of incubation, the plate is washed, the substrate is added, and the reaction is completed by adding the termination solution after half an hour of light-proof reaction, and then it is read. The value is used to determine whether the result is negative or positive. Rubella infections are generally mild in adults, but fetal infections can be extremely serious. Congenital rubella syndrome (CRS) may manifest as transient abnormalities including purpura, splenomegaly, jaundice, meningitis, thrombocytopenia, or as permanent disorders such as cataracts, glaucoma, heart disease, deafness, microcephaly, and mental retardation. In addition, distant complications may include diabetes mellitus, thyroid abnormalities, precocious puberty and progressive rubella holoprosencephalitis. It was found that the incidence of fetal infection is highest at 11 weeks of gestation again and that the incidence of congenital defects is highest in early gestation (90%) and decreases progressively in mid to late gestation. The diagnosis of intrauterine fetal infection is difficult and is made by testing for rubella-specific IgM antibodies in fetal blood specimens and by isolating the virus from amniotic fluid and pregnancy products. There is no effective treatment for rubella virus infection and termination of pregnancy is the only effective treatment. In your case, now 18 weeks pregnant, the acute phase of infection, recede 2-3 weeks incubation period, the risk of intrauterine infection of the fetus is still relatively high, you can judge the time of infection according to the time of appearance of your symptoms (fever, joint pain, swollen lymph nodes behind the ear, etc.) probably, according to your pregnancy wishes to decide whether to continue the pregnancy.